The Big Top

{T}: Add one mana of any color that appears on your top. (A top is an outerwear garment worn on the upper body.)

Swamp

Jack-in-the-Mox

{T}: Roll a six-sided die. This ability has the indicated effect.
1 — Sacrifice Jack-in-the-Mox and you lose 5 life.
2 — Add {W}.
3 — Add {U}.
4 — Add {B}.
5 — Add {R}.
6 — Add {G}.

Organ Harvest

Your team may sacrifice any number of creatures. For each creature sacrificed this way, you add {B}{B}.

Summon the Pack

Open a sealed Magic booster pack, reveal the cards, and put all creature cards revealed this way onto the battlefield under your control. They're Zombies in addition to their other types. (Remove those cards from your deck before beginning a new game.)

Have

Primeval Titan

Trample
Whenever Primeval Titan enters or attacks, you may search your library for up to two land cards, put them onto the battlefield tapped, then shuffle.

Griselbrand

Flying, lifelink
Pay 7 life: Draw seven cards.

Spike, Tournament Grinder

({B/P} can be paid with either {B} or 2 life.)
{B/P}{B/P}{B/P}{B/P}: Reveal a card you own from outside the game that has been banned or restricted in a Constructed format and put it into your hand.

Animate Graveyard

Enchant your graveyard
Enchanted graveyard is a creature on the battlefield with base power and toughness each equal to the number of cards in it. It has the text boxes of all creature cards in it. It's still a graveyard.
If enchanted graveyard would leave the battlefield, instead exile Animate Graveyard.

Jund 'Em Out

Retrace (Sorry, no room for reminder text.)
Choose one at random. Create a copy of the chosen card. You may cast the copy without paying its mana cost.
• Abrupt Decay
• Blightning
• Bloodbraid Elf
• Lightning Bolt
• Liliana of the Veil
• Tarmogoyf

Eye to Eye

You and target creature's controller have a staring contest. If you win, destroy that creature.

Uncharted Haven

Uncharted Haven enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.

Booster Tutor

Open a sealed Magic booster pack, reveal the cards, and put one of them into your hand. (Remove that card from your deck before beginning a new game.)

Uro, Titan of Nature's Wrath

When Uro enters, sacrifice it unless it escaped.
Whenever Uro enters or attacks, you gain 3 life and draw a card, then you may put a land card from your hand onto the battlefield.
Escape—{G}{G}{U}{U}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Urza, Academy Headmaster

+1: Head to AskUrza.com and click +1.
−1: Head to AskUrza.com and click -1.
−6: Head to AskUrza.com and click -6.

Karakas

{T}: Add {W}.
{T}: Return target legendary creature to its owner's hand.

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Park Map

{1}, Sacrifice Park Map: Search your library for a land card that doesn't have the same art as a permanent you control, reveal it, put it into your hand, then shuffle.

Hangman

As Hangman enters, secretly note a word with six to eight letters.
{1}: Target player who doesn't control Hangman guesses the noted word or an unguessed letter in that word. If they guess wrong, put a +1/+1 counter on Hangman. Any player may activate this ability.
When a player guesses the noted word or all of its letters, sacrifice Hangman.

Temur Elevator

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
{T}: Add {G}, {U}, or {R}. If you don't have the city's blessing, you lose 1 life.

City of Ass

City of Ass enters tapped.
{T}: Add one and one-half mana of any one color.

Mother of Goons

Whenever a creature an opponent controls dies, sacrifice Mother of Goons unless you insult that creature.

Richard Garfield, Ph.D.

You may play cards as though they were other cards of your choice with the same mana cost. You can't choose the same card twice. (Mana cost includes color.)

Hidden Necropolis

Hidden Necropolis enters tapped.
{T}: Add {B}.
{4}{B}, {T}, Sacrifice Hidden Necropolis: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Proxy

Chaos Orb

{1}, {T}: If Chaos Orb is on the battlefield, flip Chaos Orb onto the battlefield from a height of at least one foot. If Chaos Orb turns over completely at least once during the flip, destroy all nontoken permanents it touches. Then destroy Chaos Orb.

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Blacker Lotus

{T}: Tear Blacker Lotus into pieces. Add four mana of any one color. Remove the pieces from the game.

Sol Ring

Public Thoroughfare

Public Thoroughfare enters tapped.
When Public Thoroughfare enters, sacrifice it unless you tap an untapped artifact or land you control.
{T}: Add one mana of any color.

Golos, Tireless Pilgrim

When Golos, Tireless Pilgrim enters, you may search your library for a land card, put that card onto the battlefield tapped, then shuffle.
{2}{W}{U}{B}{R}{G}: Exile the top three cards of your library. You may play them this turn without paying their mana costs.

Captivating Cave

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{4}, {T}, Sacrifice Captivating Cave: Put two +1/+1 counters on target creature. Activate only as a sorcery.

Wrenn and One

+1: Wrenn and One gains "{T}: Add {G} until your next turn.
−1: Create a 1/1 green Squirrel creature token.
−4: You get an emblem with "At the beginning of your precombat main phase, add {G} for each creature you control."

Attempted Murder

Choose target creature. Roll X six-sided dice. For each even result, put two -1/-1 counters on that creature. For each odd result, create a 1/2 blue Bird creature token with flying named Storm Crow.

Crystal Grotto

When Crystal Grotto enters, scry 1.
{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Shimmerdrift Vale

Shimmerdrift Vale enters tapped.
As Shimmerdrift Vale enters, choose a color.
{T}: Add one mana of the chosen color.